The present invention relates to a pull-out guide assembly for drawers comprising a first and at least one second rail, wherein arranged between those two rails is at least one running carriage with load-transmitting rolling bodies. The running carriage—in particular upon a deviation from the differential movement between the rails—can be coupled to the second rail.
As a result of the slip between the rollers of the running carriage and the guide profiled sections of the rails, it is not always guaranteed that, when the drawer is pulled out and pushed in, the running carriages cover exactly half the travel distance of the pull-out rail. That results in what are referred to as running carriage errors, in which the position of the running carriage is not correct in relation to the carcass and pull-out rail. Carriage running errors of this kind can in some cases result in the drawer staying open in normal use.
The problems involved with such running carriage errors are known in the state of the art and repeatedly occur in the case of pull-out guide assemblies in which the load of the drawer is transmitted by rollers which are not borne on the rails but in separate running carriages. If the drawer is only moved manually, these errors are in many cases not noticed. If the drawer is pulled into the fully closed position by a conventional closure system with springs, then in most cases there is so much momentum for the carriage running error to be corrected by the dynamic of the drawer and for the drawer always to close.
In the case of pull-out guide assemblies with a closure device, additional damping devices are frequently provided. These devices damp the drawer over the last motion distance to the respective end position, so that the drawer is not pulled into the furniture body or carcass with too much force. However, these damping devices reduce the closing dynamic of the drawer such that a carriage running error occurring while the drawer is moving can no longer be compensated due to the lack of kinetic energy.
A solution for overcoming that problem is described for example in European patent specification EP 1 393 654 B1 issued to the present applicants. In that case, the running carriages are provided with arresting means which, upon a deviation from the differential movement between the rails, arrest the running carriage at predetermined locations between the two end positions with respect to one of the rails. That arresting action is releasable by displacement of the rails relative to each other. After release of the arresting effect, the running carriages are movable beyond the predetermined locations in the direction of the end positions. That arrangement therefore ensures that correction of the position of the running carriage is effected before it has reached the end region of the retraction path.